Hydraulic press with continuously rotating dial



Mrch 14, 1950 w. A. FLETCHER Erm.

HYDRAULIC PRESS WITH CONTINUOUSLY ROTATING DIAL Filed Sept. 5, 1946 5Sheets-Sheet 1 INVENTORS March 14, 1950 w. A. FLETCHER ETAL 2,500,671

HYDRAULIC PRESS WITH CONTINUOUSLY ROTATING DIAL 5 Sheets-Sheet 2 FiledSept. 5, 1946 March 14, 1950 w. A. FLETCHER Erm. 2,500,671

HYDRAULIC PRESS WITH CON'I'INUOUSLY ROTATING DIALl Filed Sept. 5, 1946 5Sheets-Sheet 3 Va@ Mw@ Mx im "o INVENTOR Bv 'Mv March 14, 1950 w. A.FLETCHER ErYAL 2,500,671

HYDRAULIC PRESS WITH CONTINUOUSLY ROTATING DIAL I 5 Sheets-Sheet 4 FiledSept. 5, 1946 March 14, 1950 w. A. FLETCHER ETAL HYDRAULIC PRESS WITHCONTINUOUSLY ROTATING DIAL Filed Sept. 5, 1946 5 Sheets-Sheet 5 l /l/l l/l /l/l/l/ Potented Mar. 14, 1950 HYDRAULIC PRESS WITH CONTINUOUSLYROTATING DIAL William A. Fletcher, Basil S. Sample, and Max E. Todd,Anderson, Ind., assignors to General Motors Corporation, Detroit, Mich.,a corporation of Delaware Application September 5, 1946, Serial No.695,000

2 Claims. (Cl. 113-45) This invention relates to presses for performingoperations on work-pieces which are placed on workholders moved by aconveyor from a loading station to a position under the ram of a press.A press of this type is commonly known as a dial feed press, theconveyor being a rotatable table or dial which is moved intermittently.During the rest period of the dial, the ram of the press moves a toolagainst the workholder underneath. 4

- When handling certain kinds of Work-pieces, it

is not always convenient or practical to secure them to the workholdersin a manner such that they will always remain in place upon theworkholders during the starting and stopping of the conveyor or dial asit carries the work from the loading station to the work stationunderneath the press tool.

Therefore, it is an object of the present invention to provide a presshaving a continuously moving conveyor or dial and to provide formovement of the support for the press tool laterally with the dialduring a portion of the dial movement so that the tool'will remain inalignment with the work While moving toward it. Accordingly, thedisclosed embodiment of the invention comprises a conveyor such as adial, carrying a plurality of workholders, means for moving the dialcontinuously, a ram for supporting a tool movable into engagement withthe work on a workholder, means -for moving the ram toward and away fromthe work, means for causing the ram to move laterally with the conveyorduring a portion of its movement when the tool carried by the ram movesinto engagement with the work i and means for returning the ramlaterally to a starting position.

The further objects and advantages of the present invention willbeapparent from the following description, reference being had to theaccompanying drawings wherein a preferred embodiment of the presentinvention is clearly shown.

In the drawings:

Figs. l and 1A together constitute a plan view of a press embodying thepresent invention.

Fig. 2 is a front elevation;

Fig. 3 is a sectional View on line 3-3 of Fig. 1;

Fig. 3A is the top view of a piston rod shown in Fig. 3;

Fig. 4 is a s-ide elevation partly in section, the part in section beingon the line 4-4 of Fig. 2;

Fig. 5 is a diagram of hydraulic circuits.

Referring particularly to Fig. 3, there is a base.

I0, or table top which is supported above the floor level in anysuitablemanner, not shown. Base Ill supports a fixed rod II and a rollerthrust bearing I2 which supports one arm I3 of a C- shaped frame I5having an arm I4 also journaled on the rod II. Upward movement of the C-frame I5 is restricted by a roller thrust bearing I6 clamped against ashoulder I'l of the rod II by nuts I8 threaded on the rod and located ina recess I9 closed by a cover 20 attached to the frame I5. A dial 2| isjournaled on the rod Il and is located between the arm I3 of the C-frameI5 and a collar 22 pinned to the rod Il. The weight of the dial 2l istransmitted to the base I0 through a thrust ball bearing 23, the hub ofarm I3 of C- frame I5 and the thrust roller bearing I2. The dial 2|carries a plurality of workholders equiangularly spaced adjacent theperiphery of the dial. One of these workholders is represented by theblock 25 which obviously would be shaped to conform to. the Work-pieces.holder 25 is located for the press operation, it is above the planesurface 26 of a pad provided by the arm I3 of C-frame I5 so that thepressure exerted by the press tool upon the work tending to deflect thedial will cause the dial to be pressed against the surface 26.

The dial 2I is rotated continuously by an electric motor, not shown.Referring to Fig. 2, the

motor is connected by a belt drive with a pulley 30 which, through aspeed reducing mechanism 3l, drives a shaft 32 connected by a coupling33 with a shaft 34 journaled in-bearings 35 and 36 (Fig. 4) supported bya bearing frame 31 attached to the base I0. The shaft 34 provides apinion 38 meshing with a gear 39 attached to the underside of the dial2I. A gear ratio between the shaft 34 and the dial 2l corresponds to thenumber of workholders 25 on the dial. For example, if the dial carriestwelve Workholders, the speed ratio of the shaft 34 and dial 2| is l2to 1. Therefore, the pinion 38 may have twelve teeth and the dial 144teeth. For each revolution of the shaft 34 the dial will rotate 30 whichis the angular spacing of the twelve workholders on the dial.

Since the shaft 34 makes one revolution during each press cycle it maybe used to control the movement of the press ram to be described.Accordingly, the shaft 34 drives a cam 40 which engages a roller 4Icarried by a valve rod 42 of an oil pressure distributing valve 43 to bedescribed. Valve 43 is supported by bracket 44 attached to the tableIII, said bracket `supporting also the speed reducing gear 3l.

The c-frame I5 includes a tubular part 50 (Fig. 3) which carries asleeve 5I and a head 52 When the Workadjustment is made rotation of thepiston is prevented by a lock nut 51.

The lower end of rod 55 provides a piston 58 fitting the inner wall of acylinder or ram 59` which is guided for vertical movement by sleeveAxial rotation of the cylinder 59 is prevented by a key 60 which slidesin a vertical groove 62 provided by the sleeve 5|. The key 60 is iixedto the cylinder 59 -by a nut 6I which has sliding t with theA rod 55 andwhich closes the upper end of the cylinder 59. The rod 55 is providedwith passages 64 and 65 into which pressure oil is distributed by thevalve 43 (Fig. 4). When passage 64 is connected with the pressure sourceand 65 is connected with drain, cylinder 59 will move down until thelower end of nut 6I engages 1 the upper side of the piston 58. Whenpassage 65 is connected with the pressure source and passage 64 withdrain, the cylinder 59 will move up until the nut 6| engages the flange52a of head 52. The frame I5 provides an oil seal 66 for vpreventing thepassage of oil downwardly from the lo-wer end of the cylinder 59. Theoil which accumulates above the seal is conducted through passage 61connected by a pipe, not shown, with drain or tank.

The lower end of the cylinder or ram 59 provides for attachment theretoof a tool for performing an operation upon the workpieces carried by theworkholders.

ibut it will be understood to be one which is designed to perform aparticular operation.

The head 52 supports a valve 10 moved into engagement with a valve seat1I by a spring 12 which surrounds the valve stem and is conned between asurface 13 of the head and a washer 14 retained on the valve stem by apin 15. The head 52 has a hole 16 which provides clearance around thevalve stem. The valve 10 moves in a recess 11 closed by a nut 18. Apassage 19, which is connected with one of the pressure lines to the Thetool is not shown piston in a manner to be described, connects dialwhile the tool is moving into engagement with the work. For this purposethe dial is provided with pins 90 (Figs. 1 and 4) equi-angularly spacedand equal in number to the number of workholders 25. Acarried by theC-frame I5. Dog 9| is a lever attached to a shaft 92 which extendsthrough a spacing collar 93 (Fig. 4) and through bearings 94 ina'bearing bracket 95 attached to the frame I5. A spring 96 whichsurrounds the spacer 93 urges the dog 9| clockwise as viewed in Fig. 1or looking in the direction of arrow 91 (Fig. 4), said motion beingarrested when a lever 98 attached to the lower end of the shaft 92engages Each pin 90 engages a dog 9| a stop pin 99 fixed to the bracket95. Lever 98 l carries a roller |00 for engagement by a cam surface |0Iprovided by a bracket |02 having a slot table or base I0 (Fig. 2).

Awithin the cylinder III urges an arm I| 4 clock- |03 through whichscrews |04 extend which are threaded into the table I0. The

an adjustment of the bracket |02.

The dial 2| rotates counterclockwise as viewed in Fig'. 1. Therefore,when the pin 90 engages `slot provides the dog 9| the C-frame I5 willmove laterallyv with the dial about the dial axis O. Fig. 1 showsC-frame I5 in a. position represented by its center line C-O which isbetween its limits of travel. At that instant, the pin which engages thedog 9| is on line B-O and the pin 90' which is next to engage the dog isvon line A-O. At a position to the right of C-O theipin 90 engaged thisdog 9| and started movement of the frame I5. As the frame I5 startsmoving with the dial 2|, cam 40 which rotates clockwise as viewed inFig. l, causes the valve rod roller 4I to move up (Fig. 1) to causevalve 43 to be conditioned for effecting downward movement of the ram59. A latch to be described maintains the valve 43 in that conditionindependently of the cam 40. Fig. 1 shows that the cam 40 is about toleave the roller 4|. At a position of the frame I5 to the left ofB-O,through the coaction of surface I 0I of bracket |02 and roller |00, thedog 9| will be moved counterclockwise away from the path of movement ofthe pin 90 so that the frame I5 can be returned by means to be describedto a starting position at the right of C-O, and th'e dog 9| Iwill bereturned by spring 96 (Fig. 4) to a position when the dog will beengaged by the next pin 90 which had lbeen moving to the left of A-Owhile the frame I5 had been moving to the left of C-O.

Before the disengagement of the dog 9| from roller 90, the cam 40 hadentirely released the roller 4| so that by means responsive to thecompletion of the operation upon the work by the ram supported tool, thevalve latch is retracted in a manner to be described and a spring causesthe valve 43 to be conditioned for causing the ram 59 to be lifted.

The return of the frame I5 from a position to the left of C-O to aposition to the right of C-O Is eiected by the instrument IIO commonlyknown as a door closer. The door closer I|0 comprises a cylinder II Ihaving a mounting pad II2 attached to a bracket II3 supported by the Aspring, not shown,

Wise (Fig. l) about its axis II5. Arm II4 Iis pivotally connected at II6 with an arm I I 1 pivotally connected at I|8 with a lever II9pivotally con' nected at I 20 with a bracket I2I which screws |22 attachto the frame I5. The door closer IIIJ includes a pneumatic or hydrauliccheck which retards the clockwise return movement of thel frame I5. Thecheck can be adjusted to .vary the time of return of the frame I5 to astarting Iposition. 'I'he frame I5 -is timed to return to its startingposition just before the next pin 90' moves into engagement with the dog9|. Consequently the oscillation of the frame I5' is almost continuous.The object is to return the frame I5 to its starting position just intime for the dog 9| -to be engaged by the next pin 90 which is movingasodevi cylinder |31 receives a piston |39 which provides a valve whichis held upon a seat |4| by the force of a spring |43 and by the pressureof oil above the piston |39, said oil entering through a small passage|42. A central passage |44 in the rod of piston |39 leads from a chamber|45 in the head |38 to a passage |46 below the seat |4I connected bypipe |41 with the tank. The head |38 is provided with a passage |48connecting cylinder |31 with a valve seat |49 normally closed by ballvalve urged against the seat by a spring |5|, the pressure of which isadjusted by screw |52.

The passage |34 is connected by pipe |54 with port provided by the body|56 of the valve unit 43. A port |51 is connected by pipe |58 withpassage 64 in the piston rod 55. A port |59 in body |56 is connected bypipe |60 with passage 65 in the piston rod 55. The valve body |56provides exhaust ports |6| and |62 connected by a passage |63, connectedby pipe |64, connected with pipe |41. Pipe |65 connects pipe |60 withpassage 19 leading into the chamber 11 of the head 52 as shown in Fig.3. Passage 80 is connected by pipe |66 with pipe |41. The valve rod 42provides a land |10 for controlling ports |51 and I6| and a land |1| forcontrolling port |59 and |62. A spring |12 urges the valve rod 42 towardthe right so that the roller 4| (Fig. 4) may engage the cam 40. Thevalve rod provides a shoulder |13 for engagement by a -pin |14 extendingfrom a piston |15 received by a cylinder |16 provided by the valve body|56. A spring |11 urges the piston |15 upwardly in Fig. 5. A pipe |18connects passage |48 of the valve unit |35 with the cylinder |16.

Fig. 5 shows the status of the valve 43 after the cam 40 (Figs. 1 and 4)has moved the valve rod 42 left into the position shown in' Fig. 5 tolpermit the spring |11 to push the pin |14 between the shoulder |13 andthe land I1|. The valve rod 42 is then held in that position temporarilyindependently of the cam action. The pump is then connected by passage|34 and pipe |54, port |55, |51 and pipe |58, passage 64 with the lowerside of piston 58 thereby causing the cylinder or ram 59 to movedownwardly to cause the tool carried thereby to engage the work. Whenthe tool has completed its operation, downward movement of the ram 59ceases and pressure increases in the -passage |34 of the valve unit |35.When the pressure exceeds the limit for which the spring |5| isadjusted, the ball valve |50 opens and Ipressure above the piston |39decreases because oil can discharge from the cylinder |31 through thepassages |48 and |44 faster than it can enter through the smallerpassage |42. Then the spring |43 is no longer able to maintain thepiston |39 down; and the valve |40 lifts from the seat |4| therebypermitting the pump to discharge back to the tank through the pipe |41.

When pump pressure is thus relieved the pressure in the cylinder |16 ofthe valve unit 43 de creases and the pressure within the valve body |56acting upon the stop pin |14 and the upper end of the piston |15 issufficient to overcome the spring |11 thereby pushing the pin |14 away'i from the shoulder |13 whereupon the spring |12 6 |55 and |59while'land |10 blocks communication between ports |55 and |51 andpermits connection between port |51 and |6|. Therefore, While piston rodpassage 64 is connected by the pipe |64 with tank, piston rod passage 65is connected with pipe |54. Therefore, pressure iluid is being admittedto the upper side of the piston 58 while the lower side is connectedwith the tank. Therefore the cylinder or ram 59 will movel up. As itdoes so, it lifts the valve 10 for the purpose of relieving pressure onthe pump independently of the action by the valve unit |35. Because thepiston rod 55 and the head 52 are movable laterally with the C-frame I5,the pipes |58, |60, |65 and |66 are provided respectively with flexiblesections |56a, |60a, |65a and |66a.

The attendant who loads the workpieces on.

the workholders usually sits in front of the dial as viewed in Fig. 2,which is below Fig. 1. It has been found that there is no disadvantageto the attendant to load a Workholder on a continuously moving dial. Theattendant soon becomes accustcmed to the steady movement of the dial. Infact it is less trying to load a steady moving dial than one which stopsand starts intermittently. Since more than normal loading time may beconsumed in loading a workholder it may happen that the attendant isstill loading the dial when it suddenly starts moving. He may not thenbe ready to release the part he has placed on the workholder, and thepart may become dislodged before he releases hold of it. With acontinuously moving dial this difliculty is not present. Furthermore,there is no jerking of the dial by starting and stopping such as todislodge the pieces which the attendant has placed upon the workholder.Therefore, for certain kinds of work where it is not practical orconvenient to clamp the workpieces to the workholder or secure them in amanner which will resist any -jerking of the dial, a press having acontinuously moving dial is a decided advantage.

vThe guard |25 (Fig. 3) which is attached to the table I0 protects theattendant from the gear 39.

While the embodiment of the present invention as herein disclosed,constitutes a preferred form, it is to be understood that other formsmight be adopted, all coming within the scopel of the claims whichfollow.

What is claimed is as follows:

' 1. A press comprising a conveyor carrying work holders for supportingwork pieces, means for moving the conveyor continuously, a ram forsupporting a tool which `engages a work piece when aligned with the ram,an hydraulic servomotor for moving the ram toward and away from the workpiece in alignment therewith, an oil supply tank, a pump for forcing oilfrom the tank under pressure to the hydraulic means, a valve forcontrolling the application of pressure oil to the servo-motor, saidvalve being actuatable into a status for causing the ram toV move towardthe work piece and being actuatable into another status for causing theram tomove away `vfrom the work piece, cam operated means cowill movethe valve rod 42 to the right. The cam y 40 is so constructed thatbefore downward movement of the ram is arrested the low land of theordinated with movement of the conveyor for causing the valve to beactuated into the first status, a spring for causing the valve to beactuatedinto the second status, a latch for temporarily holding thevalve in the rst status, a pressure relief valve responsive to theapplication of a certain pressure by the ram on the work piece forcausing the load on the pump to be relieved, means responsive to actionof the pressur@ relief 'valve for causing retraction of the latchwhereby the spring can actuate the valve into the second status, meansfor causing the ram to move laterally with the conveyor during a portionof its movement when the ram .is aligned with the Work piece, and meansfor causing lateral return movement of the ram to a starting position.

2. A press comprising a conveyor carrying work holders for supportingwork pieces, means for moving the conveyor continuously, a ram forsupporting a tool which engages a work piece when aligned with the ram,an hydraulic servomotor for moving the ram towardV and away from thework piece in alignment therewith,v an oil supply tank, a pump forforcing oil from the tank under pressure to the hydraulic means, a

valve for controlling the application of pressure oil to theservo-motor, said Valve being actuatable into a status for causing theram to move toward the work piece and being actuatable into anotherstatus for causing the ram to move away from the work piece, camoperated means coordinated with movement of the conveyor for causing thevalve to be actuated into the first status,

'a spring for causing the valve to be actuated into the second status, alatch for temporarily holding the valve in the first status, a pressurerelief valve responsive to the application of a certain pressure by theram on the work piece for causing the load on the pump to be relieved,means responsive to action of the pressure re- `REFEREN CES CITED Thefollowing references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 441,260 Tybel'g Nov. 25,v 18901,136,275 Roenrich Apr. 20, 1915 1,692,771 Ferris Nov. 20, 19282,028,225 Larson Jan. 21, 1936 2,055,530 Hallenbeck Sept. 29, 19362,122,356 Bullard June 28, 1938 2,249,964 Lindner July 22, 19412,276,979 Jacobi Mar. 17, 1942 2,362,054 Denison Nov. 7, 1944 2,425,170Wunsch Aug. 5, 1947

